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