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