If you would like grid lines that go across the graph, you can make the following call to svg_1d_plot:

my_plot.y_major_grid_on(true)
       .y_minor_grid_on(true);

To style it, you would use the following calls:

my_plot.y_major_grid_color(lightgray)
       .y_minor_grid_color(whitesmoke);

This will produce something like the following image:

For an alternate way to display a regular axis, you can use an external style:

my_plot.y_external_style_on(true);

When there is a call to the plot() method, define _area_fill_color

multimap<double, double> my_data;
svg_2d_plot my_plot;

my_plot.plot(my_data, "Data", _area_fill_color(red));

This produces the following image:

If you would like an interpolated curve shown over your data, simply use the following command:

my_plot.plot(data, "Series 1", _bezier_on = "true");

This produces something like the following images: