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