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