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