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