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