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