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