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)(15,20)(16,21)(17,27)(18,23)(19,24)(22,25)(26,28) involution — undirected(1,2,4,3)(5,7)(6,9)(8,11)(10,12)(13,15,19,26)(14,20,24,28)(16,25,18,17)(21,22,23,27)(6,10)(7,11)(13,16,19,18)(14,21,24,23)(15,25,26,17)(20,22,28,27)(6,10)(9,12)(13,17,18,15,19,25,16,26)(14,22,23,28,24,27,21,20)(1,3,4,2)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.