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