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