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