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