I would share it, but BigCorp would come after me. It is nothing terribly smart really. I am using steampipe to list all the regions for VPC/Subnets/NAT GW/IGW/[everything else networky] and loop through the list adding nodes to the diagram. There is a long list of accounts which all gets generated and committed in a git repo. The big challenge was to make it all readable instead of making a mess.