The most common option is to show the graph after each item. This allows for discussion as you go through the list of elements. You may however have a lot of elements to get through, and it is sometimes a lot faster to speed on through without the graphs displayed. For this situation you can either have the graphs at the end of the activity, or not shown at all.
When you are not showing graphs after each element, you can also choose whether the software automatically moves onto the next element or whether the facilitator must select to move on after a pause. This can be used to discuss the elements before they appear.