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