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