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