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