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