Natural hair color once it started turning gray or white in certain nutrients deficits and health conditions may spawn premature gray hairs. But you can do some DIY homemade hair dye, Coffee works as a natural tonic for hair, which stimulates cell growth and darkens the light grey hair into natural colors without fuss. Take 1/2 c of brewed espresso, mix it up with 1/2 a cup of conditioner, and then add 1 tablespoon of coffee grounds. Apply it as a mask for 60 minutes and then rinse it off.
Would be to use a grey hair dye, henna, or other natural hair dye. You could also try using hair oil or hair masks to nourish the hair and keep it healthy in order to maintain its natural color. Additionally, if you are looking for a more permanent solution, you could try using a professional colorist or salon treatment to color your hair.