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