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