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