First, access your administrator settings by visiting www.yourwebsitename.com/admin and entering your username and password.
Under the Users tab, click the Permission Groups tab.
Click Delete next to the group you want to delete.
You’ll be asked if you want to permanently delete the group and its settings. Make sure you are positive that you want to delete the group, otherwise you’ll have to go through and create the group and set its permissions over again.
If you are sure you want to delete the group, click OK.