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