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