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