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