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