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