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)(11,14)(12,15)(13,16)(17,21)(18,22)(19,23)(20,24)(26,32)(27,36)(29,30)(33,34)(35,40)(37,38)(9,11)(10,14)(12,19)(13,18)(15,23)(16,22)(17,20)(21,24)(25,26,31,35)(27,37,36,33)(28,38,39,34)(29,32,30,40)(2,5)(6,8)(9,12,13,20)(10,15,16,24)(11,17,18,19)(14,21,22,23)(25,27,31,36)(26,33,35,37)(28,29,39,30)(32,38,40,34)(11,18)(14,22)(17,19)(21,23)(25,28)(26,34)(27,29)(30,36)(31,39)(32,33)(35,38)(37,40) involution — undirected(1,3,4,7)(2,6,5,8)(10,16)(14,22)(15,24)(21,23)(25,29,31,30)(26,32,35,40)(27,28,36,39)(33,34,37,38)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.