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