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)(13,14,17,21)(15,23,25,19)(16,20,24,28)(18,22,26,27)(5,6)(7,10)(8,12)(9,11)(15,24)(16,25)(18,26)(19,20)(22,27)(23,28) involution — undirected(1,2,3,4)(13,15)(14,19)(16,18)(17,25)(20,27)(21,23)(22,28)(24,26)(5,7,9,8)(6,10,11,12)(5,8,9,7)(6,10,11,12)(13,16,17,24)(14,20,21,28)(15,18,25,26)(19,27,23,22)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.