Did you see this post, you need to extract the folder named networkx and place this in a path that is readable by the Rhino Python interpreter (i.e. by adding it to the module search paths, or directly in the code itself). Have attached networkx 1.5, which will (mostly) work with the IronPython version used by Rhino. If you unzip this to a folder in the module search paths and restart Rhino, you should be good to go.
networkx.zip (414.0 KB)
Edit: Here’s the archived version, for full context:
https://networkx.github.io/documentation/networkx-1.5/
Edit II: Of course it’s a real shame that versions beyond 1.5 do not (yet) play nice with IronPython. But I’ve used it quite a lot for many different things, and have yet to find a better (in terms of features, versatility and simplicity) graph library for use with GHPython (including QuickGraph). Also note that you can “patch” it, by copying functions from future versions over and implementing these directly.