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