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