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