Hello @watanabeshuji,
My team and I are currently working on automated generation of architecture diagrams for CloudFormation and Serverless projects. Your project is particularly interesting as it represents a good real-world use case.
The tool we are working on generated the following diagram for your repo. I am happy to get your feedback about it. You would help us a lot.
Does the diagram match the architecture you have in mind?
Cheers,
Asha