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