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