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