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