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