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