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