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