displaying 3 factors and 1 continuous variable in one plot using ggplot2

I have three factors and one discrete variable, how we can plot in one plot, I can not differentiate fill and color because they have similar colors in the legend

    ggplot(BL_DS, aes(y= number, x=Species, 
                       color=age.sex, fill= Habitat))+geom_point()

if you aren't happy with automatic colour scales. then you can define your own.
see the examples: