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