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