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