One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,5)(6,8)(10,16,19,25)(11,21)(12,17)(13,23)(14,27)(18,34,36,40)(20,38,35,31)(22,28)(24,33)(26,39)(29,32,37,30)(2,5)(6,7)(9,10,17,32,28,36,26,38,27,35,39,34,23,37,12,25,15,19,21,30,13,18,24,31,14,20,33,40,22,29,11,16)(1,3,4,8)(2,6,5,7)(9,11,22,33,14,24,13,21,15,12,23,39,27,26,28,17)(10,16,29,40,20,31,18,30,19,25,37,34,35,38,36,32)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.