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