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