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