Specify the default fill types for groups in graphs

File > Options > Graphics > Data View With Groups > Fill Types

For graphs that have areas, bars, boxes, or pie slices, you can assign a different fill type to each group. Specify the default number and types of fills that are available. The changes you make to the defaults remain until you change them again, even after you exit Minitab.

If the number of groups in the data is higher than the number of available fill types, then Minitab repeats the fill types.