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