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