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