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