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