Toast the shredded coconut in a dry skillet over medium heat for 3-4 minutes, stirring frequently, until golden brown and fragrant. Let cool completely.
In a large jar or pitcher, combine the ground coffee, cold water, and toasted coconut. Stir well, cover, and refrigerate for 12-24 hours.
Strain the cold brew through a fine-mesh sieve lined with cheesecloth or a coffee filter into a clean container, discarding the grounds and coconut.
To serve, fill glasses with ice and pour cold brew concentrate over ice, diluting with water to taste if desired.
Top each glass with coconut milk and simple syrup, stirring gently to combine before enjoying.