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