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