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)(13,14,19,23,18,22,16,21)(15,24,26,28,25,20,27,17)(6,9)(7,11)(13,15)(14,20)(16,27)(17,23)(18,25)(19,26)(21,28)(22,24) involution — undirected(1,2,3,4)(15,25)(17,28)(20,24)(26,27)(5,7,8,11)(6,10,9,12)(13,16,18,19)(14,21,22,23)(15,26,25,27)(17,24,28,20)(6,9)(10,12)(13,17,19,24,18,28,16,20)(14,15,23,26,22,25,21,27)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.