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