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