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