Origin can't link the project name to Graph name. But any time you change the project name, you can open the project file and run the script below to set all graphs longname to project name:
doc -e p {
page.LONGNAME$=%g;
}
To run a piece of script in Origin, select from menu Window:Script Window. Paste the code, then select all the code with the cursor (selected text will be highlighted), and press Enter.
James