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