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