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