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