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