You cant. Facebook allows your friends to add you to any group without your permission.
However, you can use Facebook Groups Leaver free chrome extension developed by me to leave all groups you are in.
Facebook Groups leaver extension will leave all the groups you are in:
1- Select all group you dont want to leave MAKE SURE TO SELECT GROUP YOU ARE ADMIN IN.
2- Click 'Leave Groups!' button to start leave all groups except the selected ones.
فيديو عربي يشرح تحميل الاضافة واستخدامها :
For suggestions or reporting a bug in any extensions, open this page ( click her). then scroll down and leave it in comments