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