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