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