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