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