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