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