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