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