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