There is no built in way to return to the original layout. Only a developer should be canceling a running script with esc (windows) or Command Period (Mac). As a developer you can return to the original layout by selecting the layout from the layouts menu.
If you give the user the option to cancel the script by clicking a button, you should build additional steps that take them back to the original layout such as go to layout [<original layout>].
You can return the user to the original layout and then pause your script or you can put your own button for cancelling the script with steps like these:
Go to Layout [specify a layout, can't use original layout]
Halt Script ---> this step halts the paused script.
To pause a script so that only continue and not cancel is shown in the status area use Allow User Abort [off] to keep the cancel option out of the status area.
Thanks again Phil. Ill give it a go.