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