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