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