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