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