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