Notably, I don't want to free-design directional relationships that are counter intuitive to what people expect. Eg, if Service A calls Service B, does the arrow go to Service B? What about the response? I imagine there are a ton of little questions like this and I'd like to learn to write what people expect to see.
There are standards like UML, but I’ve never found those to be as useful to start with. It’s best to treat this as a “design problem”: first, answer the question: “what am I communicating”.
Then, maybe look into conventions - but often you’ll find less need for one “master UML diagram” and instead use many, smaller diagrams embedded within reference docs.
I feel like project reactor did a good job here: https://projectreactor.io/docs/core/release/api/reactor/core...
Personally I’d like to see more related to inheritance, but I’ll take what I can get. The tooling can be a pain to embed automatic diagrams in