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