One vertex per element, one color per generator, with an edge from x to x·s.
(5,8)(9,10)(11,18)(12,16)(13,21)(14,17)(15,19)(20,23)(22,24)(25,26,29,32)(27,33,35,40)(28,36,38,31)(30,37,39,34)(1,2,4,6)(3,5,7,8)(9,11,14,20)(10,15,17,24)(12,19,13,22)(16,23,21,18)(1,3)(2,5)(4,7)(6,8)(9,10)(11,15)(12,21)(13,16)(14,17)(18,19)(20,24)(22,23)(25,27,29,35)(26,30,32,39)(28,37,38,34)(31,40,36,33)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,24,18)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.