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