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