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