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