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