Resolved: Specifying color inside a facet

Hi Joao,
thanks for reaching out! That's a great question and one of the more advanced or custom ways to build a ggplot. There are a options to changing the colors of a ggplot scatter plot.
Option 1: enter custom colors for each category like so

sp + geom_point(aes(color = Region)) + theme_light() + 
  labs(x = "Corruption Perception Index, 2015", 
       y = "Human Development Index, 2015", 
       title = "Corruption and Human Development") + 
  scale_color_manual(values=c("red", "blue", "green", "orange", "black", "grey"))

Or alternatively, you can use a different color palette, in your question you mention blue, so that's the example I chose:

sp + geom_point(aes(color = Region)) + theme_light() + 
  labs(x = "Corruption Perception Index, 2015", 
       y = "Human Development Index, 2015", 
       title = "Corruption and Human Development") + 
  scale_color_brewer(palette="Blues")

Feel free to customize the plot further with your own colors and color palettes.

Best,
365 Eli