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