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