As this novel is set in Colombia and was first published in Spanish the book has a strong Hispanic 'Latino' culture through out it.
On a past trip to Spain I captured these images, the vibrant colors reflect the culture, environment and heat of the country, similar to Colombia. Depending on the final cover design, I am considering developing the colour palette from these photographs.
Or perhaps use elements of them to drop into the design as in the below example 'barrio boy' using the mosaic tiles as the backdrop.