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