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