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