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