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)(16,20,26,27,25,22,24,28)(2,3)(5,6)(7,11)(8,10)(9,12)(14,15)(20,22)(21,23)(27,28) involution — undirected(5,7)(6,9)(8,12)(10,11)(13,15,18,14)(16,20,25,22)(17,23,19,21)(24,27,26,28)(1,3,4,2)(7,12)(9,11)(13,16)(14,20)(15,22)(17,26)(18,25)(19,24)(21,28)(23,27)(6,10)(9,11)(13,17,18,19)(14,21,15,23)(16,24,25,26)(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.