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