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