This can be achieved by setting the line properties in the plot.
The 'MarkerEdgeColor' is the outline color of the marker. Its default value is 'auto', which uses the same color as the 'Color' property of the line. This value can be accessed using the dot notation on the line object.
The following is an example code snippet:
l = plot(x,y,'o');
l.MarkerFaceColor = l.Color;