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