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