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