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