I made a diagram like this for a test automation system inside the firewall that talks to cloud providers. Using Graphviz (DOT), it was challenging to depict the system faithfully without a maze of lines from nodes on one side of the graph to the other.

I agree with the sentiment of defining a graph in code, but I really wanted to give it a nudge from time to time, like swap these two nodes so the arrows don't cross. I'm only an occasional user, so maybe there are ways to do it.