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