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