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