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