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