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