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