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