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