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