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