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