Pause Button next to Rules or Deselection of Adgroups
In the Bid Rules or Keyword Rules tab you can etiher press the pause button at the left of the rules, or "unselect all selected adgroups" that were assigned to the rule-set at the top:
Turn Off Automation for Specific Ad Groups
To deactivate the automation for single ad groups, click on the middle button showing the number of assigned ad groups (see screenshot above).
Use the third option to "select specific ad groups", and then deselect the respective ad groups you want to remove from the rule-set.