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