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