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