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