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