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