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