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