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