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