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)(11,18)(12,16)(13,22)(14,17)(15,20)(19,23)(21,24)(25,26,28,32,29,33,36,30)(27,31,35,39,34,38,40,37)(9,11,13,20,14,21,12,19)(10,15,16,18,17,23,22,24)(26,30)(28,36)(31,37)(32,33)(35,40)(38,39)(2,5)(6,8)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,18,23,24)(25,27,29,34)(26,31,33,38)(28,35,36,40)(30,37,32,39)(1,3,4,7)(2,6,5,8)(27,34)(31,38)(35,40)(37,39)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.