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