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