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