For an easy and helpful way to visualize one text (as opposed to a large corpus) Textexture is a good tool to explore. Textexture takes texts and terms turns them into Network visualizations. All you do to create a visualization of your text is copy and paste it into Textexture. The more difficult part of Textexture comes when it's time to make meaning or analyze your network graph. Network graphs can be confusing. They're often described as amorphous blobs of spaghetti and meatballs (nodes and edges) untangling them to uncover deeper meaning takes work. It wouldn't be a bad idea to browse through our section on Network Analysis before you get started with Textexture. The folks at Nodus Labs (who created textexture) also have a very helpful introductory paper on their website.
The gist of textexure's process is that account of words that to count words which occur near each other in the text. That is not to say words have to be directly next to one another, ; paragraph and sentence structures are both considered. In the network, the nodes are the words themselves while the edges (or connections from node to node) are determined by the co-occurrence between words either directly, in paragraphs or sentences. In terms of the visualization, this effectively does two things: 1. organizes groups of words into the communities they appear in (color coded) so that with a quick glance at the network, you can pick out certain themes and 2. You can also easily see what the primary theme that links the various aspects together. No. 2. is possible because Textexture runs weights the nodes based on Betweeness Centrality, that is, the bigger the node, the more paths from one node to another node in the graph run through it. For instance, after running John Henry Newman's Lectures on Justification, through Textexture, it is easy to see that the main theme or word is "Faith." Faith is not alone is only the primary node within its pink community, but links together the blue community dominated by "God" and "Christ" with the yellow community which centers on "Justification." (For our purposes, we'll disregard the red, as that comprises Newman's footnotes and appendices in Latin)
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Newman's Lectures on Justification were largely an attempted attempt by him to attack the Protestant doctrine of justification by faith alone and prescribe his method for justification which largely centered are on obedience (read: discipline) and works coupled with faith. However, reading through the graph (as opposed to linearly) we can see that faith made itself present in almost every aspect of Newman's argument, which is why it was so central. In semantic terms, Newman had to discuss the idea he was attacking "justification by faith alone" along with the idea he was prescribing "justification through faith and works" (works in most cases meaning self-discipline and obedience to the church) thus, though not the central push of Newman's argument, faith was an important component of the work. Thus, as Nodus Labs argued in their aforementioned introductory paper, this tool does a good job at finding the words "which often appear at the junctions of meaning."