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)(13,14,18,15)(16,23,25,28)(17,22,27,20)(19,26,21,24)(1,2,3,4)(5,7)(6,9)(8,12)(10,11)(13,15,18,14)(16,21,25,19)(17,22,27,20)(23,24,28,26)(7,12)(9,10)(13,16,18,25)(14,19,15,21)(17,26,27,24)(20,28,22,23)(5,7)(6,10)(8,12)(9,11)(14,15)(19,21)(20,22)(23,28) involution — undirected(7,12)(9,10)(14,15)(19,21)(20,22)(23,28) involution — undirectedA 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.