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