Combine tapioca flour, sago flour, sugar, thick coconut milk, water and salt in a mixing bowl. Stir to mix. Remove 1/3 portion of the batter and add in pink colouring. Divide pink portion into 5 equal parts, and the remaining uncoloured batter into 4 equal parts.
Lightly grease a 20x15 cm cake tin. Place one part of the pink layer into the prepared pan. Steam over medium-high heat for 3 minutes. Add a layer of uncoloured batter over the pink layer and steam for 3 minutes. Repeat with alternate layers until the final layer is done. Steam this last layer for about 7 minutes. Make sure that no droplets of water falls into the steamed layers.
Remove the kuih and leave to cool completely before cutting into diamond-shaped pieces.