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