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