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