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