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