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