Neat! Thanks for sharing. We struggled with diagramming our NSX environment in a way our network engineer could relate to, especially with a cross-vCenter config and universal objects.
Another good one is NSX PowerOps (GitHub - vmware/nsx-powerops: NSX-v Operationalization project. Automate Networking Documentation and HealthCheck. )
It gives routing information in a table format and all kinds of other good stuff in addition to the diagram. Very helpful for a configuration "snapshot" of sorts and health-checking.