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