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