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