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