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)(13,14,17,23,19,22,18,20)(15,21,25,28,16,26,24,27)(2,4)(14,20)(15,24)(16,25)(17,18)(21,26)(22,23) involution — undirected(6,9)(10,12)(13,15,17,25,19,16,18,24)(14,21,23,28,22,26,20,27)(13,16,17,24,19,15,18,25)(14,21,23,28,22,26,20,27)(5,7,8,11)(6,10,9,12)(14,22)(20,23)(21,26)(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.