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