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