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