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