A friend at work turned me on to a product called mermaid. It has an option to integrate with pandoc.
pandoc.exe -t html -F mermaid-filter.cmd -o test.html .\test.md
It can render uml diagrams from a markup language.
Here is an example of what it the code looks like:
Here is what it renders out to: https://www.burksbrand.com/static/images/diagram-1.svg
As a fan of documentation this makes modeling your code fairly painless, it also makes the source of the diagrams diff-able since they are text files.