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