Without doing it for you, the best thing I can suggest is to draw a table like this:
CV = current value, NV = next value
CV NV
000 001
001 010
010 011
011 100
100 101
101 110
110 000
Start with 3 D flip flops next to each other, with common clock. You need to work out what logic gates you can use to get from current value to next value.