Depends on what you want to achieve later with this categorization. I asume, you are using the free CB package, without any other plugins...
Just create additional fields (Checkboxes/Selects).
Or Multi-Select/Checkboxes if multiple attributes describes your users best.
That really depends on the terms or attributes you want to assign to a usertype.
e.g. create a multi-checkbox "cb_usercategory"
Values might be: Category1, Category2, Category3 ...
You can decide to show or hide these categories to the public or not.
If you want to show different UserLists based on the selected values, you have to create different userlists with a filter for the field "cb_usercategory"...
Have fun.
