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