Recently, I have been using the online diagramming tool draw.io for the AWS architecture diagrams I generate. It’s got an intuitive interface, allows for local saving of images (PDF, PNG formats), and is free to use. Most AWS services are represented in their diagram palette. draw.io supports diagram storage on Dropbox and Google Drive as well. You can create non-AWS diagrams with draw.io, too. For more details, check  out their online manual. Here’s a sample diagram I made using draw.io that is part of a recent post: