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