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