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