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