WP-GraphViz implements Graphviz, in WordPress.Graphviz is open source graph visualization software. Graph visualization is a way of representing structural information as diagrams of abstract graphs and networks. It has important applications in networking, bioinformatics, software engineering, database and web design, machine learning, and in visual interfaces for other technical domains.

If you are susceptible to this kind of thing, you know who you are. There is no cure.

You may want to check out their impressive Gallery.

The Credits page shows a line-up of top-flight people behind Graphviz. That explains it.

I had seen the previous Graphviz plugin, TFO Graphviz, which has not been updated in over 2 years. This new plugin looks much more promising.

You should give the plugin FAQ a careful read. Not fatal, but meaningful caveats.