This sounds like a similar concept to one I have raised previously, affinity mapping. The linked topic may give you some ideas - as well as some good criticism of the notion as visualisation can be a limiting factor to seeing all the connections.
As for specifically tackling this concept, TiddlyMap and TW-Whiteboard will probably get your the closest. Unfortunately, they are large, complicated and often have issues between updates, as well as numerous open bugs. I don’t blame the developers for that - they are hobby projects downstream of an already complex project. However, I have run into these bugs myself and won’t look to integrate them into my wiki as long as these issues stay around. I can get most of the value from text and dynamic tables (using Shiraz) alone.