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