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