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