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