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