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