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