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