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