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)(11,12,15,18,14,16,21,23)(13,17,20,24,19,22,25,26)(3,5)(4,7)(6,10)(8,9)(12,16)(13,19)(18,23)(20,25) involution — undirected(5,10)(7,9)(13,19)(17,22)(20,25)(24,26) involution — undirected(4,8)(7,9)(12,16)(17,22)(18,23)(24,26) involution — undirected(11,13,15,20,14,19,21,25)(12,17,18,24,16,22,23,26)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.