There is no 4D plot. You will need to do something to represent your 4D data in 2 or 3 dimensions. The most obvious thing to do is create a 3D plot for each of your trials. However, what is best is highly dependent on your data and your domain.
Most important is to create a figure that is meaningful. Perhaps with a little creativity and domain knowledge, you can find a good way to process the data so that it can be shown in 2/3D.
