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