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