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