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