$('#menu-item-56').click(function(){
  var b = !$("#navigationWrapper").hasClass('whiteSection') //less code to write
        $('#contactWrapper').toggle(b);
        $("#navigationWrapper").toggleClass('whiteSection', b)
                               .css("background-color", b ? "rgba(0,0,0,0.3)" : "rgba(255,255,255,1)");
});