With Astah Script Plug-in, you can automatically lay out the GSN nicely. This feature is very useful at the finish-up.
(1) Download the script from here.
(2) Unzip the downloaded file and save this layoutGSN.js file.
(3) Launch Astah GSN and go to [Tool] – [Script]. (To add this menu, you need to install Script plug-in first.)
(6) Then GSN should automatically be shaped nicely!