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