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