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