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