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