Yep, I wrote that as my first project in rust and it was used for a lot of the Piston project repos. Unfortunately I stopped updating that in December because breaking changes were happening too frequently for me to keep up.
I'll probably revisit it soon now that 1.0 is fairly imminent, but prs are welcome of course!
Graphviz is ok for quickly plotting a dependency graph. I have yet to see a beautiful example of auto-layouted graphs. Beautiful means getting the details right like lines not crossing at narrow angles, drawing a little "hop" when lines cross, and not being restricted to strict rows like dot.