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)(14,19)(16,17)(20,23)(21,22)(25,26)(27,28) involution — undirected(1,2,3,4)(13,14,17,21,18,22,16,19)(15,23,26,28,24,27,25,20)(6,9)(10,12)(13,15,18,24)(14,20,22,28)(16,26,17,25)(19,23,21,27)(14,21)(16,17)(19,22)(20,27)(23,28)(25,26) involution — undirected(5,7,8,11)(6,10,9,12)(15,24)(20,28)(23,27)(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.