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