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