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)(11,16)(12,13)(14,15)(17,18)(19,24)(20,21)(22,23)(25,26,30,31)(27,29,33,39)(28,35,38,32)(34,40,36,37)(1,2,4,5)(3,7,8,6)(9,11)(10,13)(12,14)(15,16)(18,23)(19,21)(26,31)(29,39)(32,35)(37,40)(2,5)(6,7)(10,15)(11,12)(17,19,22,21)(18,24,23,20)(25,27,30,33)(26,29,31,39)(28,36,38,34)(32,40,35,37)(1,2)(3,6)(4,5)(7,8)(9,12,14,11)(10,16,15,13)(17,20,22,24)(18,19,23,21)(25,28,30,38)(26,32,31,35)(27,34,33,36)(29,37,39,40)(1,3,4,8)(2,6,5,7)(9,13,14,16)(10,11,15,12)(17,21,22,19)(18,24,23,20)(25,29)(26,33)(27,31)(28,37)(30,39)(32,36)(34,35)(38,40)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.