yEd from yWorks - https://www.yworks.com/products/yed https://www.yworks.com/products/yed has excellent features (with auto-arranging of nodes for better readab

yEd from yWorks - https://www.yworks.com/products/yed https://www.yworks.com/products/yed has excellent features (with auto-arranging of nodes for better readability). Might be useful :) ps - it's FREE!