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