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