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