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