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