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