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