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