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