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