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