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