Maybe UML is a keyword to use? I found
UML::State, but
GraphViz (mentioned below!) seems rather well supported and a good idea. You're not going to get something to create pretty pictures most likely. Another avenue might be via LaTeX. Ultimately what you're doing is rendering a graph, so you actually do have quite a few choices. But you are probably not going to find something that does exactly what you want without creating it yourself. Also not what you want, but may want to see what's underneath the hood if
Bio::Graphics.
