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