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