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