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)(13,14,19,24)(15,16,21,20)(17,25,27,22)(18,28,26,23)(5,7)(6,9)(8,12)(10,11)(13,15)(14,20)(16,24)(17,26)(18,27)(19,21)(22,23)(25,28) involution — undirected(1,2,3,4)(13,16,27,23,19,20,17,28)(14,21,22,18,24,15,25,26)(6,10)(9,11)(13,17,19,27)(14,22,24,25)(15,26,21,18)(16,28,20,23)(7,12)(9,11)(13,18,17,21,19,26,27,15)(14,23,25,16,24,28,22,20)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.