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