Creating custom dependency graph for PyCharm

Hello everyone!

In my plugin, I would like to create a custom Dependency Graph - similar to the ones created with right-clicking on files and selecting show diagram option.

In this graph every node is colorized by value of its code coverage with a number in %. The dependencies would be also shown (link for example).

I would like to ask, where to start on this. Can I customize these Graphs which are created by IntelliJ based IDEs (like this)?

Or do I have to create a custom implementation for this? If yes, any advice, tutorials or where to start? Is there a way to get all the dependencies between modules, so I dont have to do a custom implementation for getting the dependencies? Is there a way to get the code coverage after test runs (some listener after tests are done)? 

Thanks in advance

Jan