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