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