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