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