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)(15,22)(18,25)(23,28)(26,27) involution — undirected(2,3)(6,10)(11,12)(13,14,16,20)(15,18,22,25)(17,19,24,21)(23,26,28,27)(1,2,4,3)(5,7,9,8)(6,11,10,12)(13,15,16,22)(14,18,20,25)(17,23,24,28)(19,26,21,27)(1,3,4,2)(14,19)(17,24)(18,26)(20,21)(23,28)(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.