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