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