You can't. You need to select something else to remove selection from active chart.
But then, why do you need to select the chart in the first place?
FYI - In older versions, when chart was selected, Excel did not highlight the data range at same time. And you were able to use ActiveChart.Deselect, but when I tested a while back on Excel 2013, it did not behave as expected and selection remained on the chart.