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