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