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