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