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