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