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