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