This guide shows you how to enable setting to automatically delete backups on VPS delete.
To enable the setting
Go to Configuration -> Master Settings from left menu.
In Master settings search for "Delete Backup on VPS deletion" setting
When you click on that checkbox a textfield will be shown named as "Number of days"
Now if you specify zero then backup will be deleted as soon as VPS is deleted, Or you can specify number of days after which you want backup to be deleted.
After this save the master settings.
Note: The VPS of which you want to delete backup should have backup plan assigned to it, Also while deleting backups it will delete backups from folder which is currently selected in backup plan of that VPS.