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