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