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