You don't - unless you do it in 3 dimensions using, say, the y- axis for the real part of the function value and the z- axis for the imaginary part of the function value. That, of course, assumes that the independent variable, x, is a real number since there is only one dimension left for it.
I see. I am a bit confused, since I have a problem asking me to plot a function with an imaginary term. Perhaps I have done it wrong (though I have looked over it and can't find an error) or I must plot in three dimensions.