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