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