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