You shouldn't be generating the text in advance and then processing it. You should be dynamically generating the text in memory, so you basically only have to worry about the memory for one text file at a time.
As for visualizations, R and ggplot2 may work (R can handle text and data munging, as well as sentiment analysis etc.) It may be worth using it as a social scientist.
ggplot2 has a python port.
That said, you are probably using nltk, right? There are some tools in nltk.draw. There is probably also a user's mailing list for whatever package or tool you are using, consider asking this there.