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