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