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