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