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