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)(14,19)(15,22)(16,18)(20,27)(23,25)(26,28)(5,7)(6,9)(8,12)(10,11)(13,14,17,19)(15,20,23,26)(16,24,18,21)(22,28,25,27)(13,15,18,22,17,23,16,25)(14,20,21,28,19,26,24,27)(7,12)(9,11)(14,19)(20,26)(21,24)(27,28) involution — undirected(1,3,4,2)(6,10)(9,11)(13,16,17,18)(14,21,19,24)(15,22,23,25)(20,27,26,28)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.