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)(11,14)(12,16)(13,15)(17,18)(19,21)(20,22)(23,24)(25,26)(27,33)(28,31)(29,32)(30,35)(34,38)(36,40)(37,39) involution — undirected(2,5)(6,8)(9,11,13,12)(10,14,15,16)(17,19,20,23)(18,21,22,24)(25,27,28,35)(26,30,31,33)(29,34,37,36)(32,40,39,38)(1,3,4,7)(2,6,5,8)(10,15)(14,16)(26,31)(27,34)(29,37)(30,38)(33,40)(35,36)(9,12,13,11)(10,16,15,14)(18,22)(21,24)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.