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