One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(6,9)(10,11)(13,14)(15,23)(16,21)(17,20)(18,22)(19,25)(24,27)(26,28) involution — undirected(5,6,8,9)(7,11,12,10)(13,15,17,24,16,25,18,26)(14,19,20,28,21,23,22,27)(14,20)(15,24)(17,18)(19,23)(21,22)(25,26) involution — undirected(2,4)(5,7,8,12)(6,10,9,11)(14,21)(15,25)(20,22)(24,26)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.