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