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