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