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