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