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