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