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