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