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