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