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