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