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