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