Thank you!
It’s actually really easy, all you need to ask for is “plantUML” (universal model language), you can then use a separate program or editor to convert the code to an actual figure.
Here’s another example with the prompt:
Write a plantUML choice diagram using the following context: “How to live like it’s 99”
You can feed GPT-4 a lot of context too, I use this to create flow charts for entire lab experiments 