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