Is there such a thing? Is camo even necessary for a rifle hunters pack?

I'm just getting back into hunting again, but have been regularly hiking, camping and fishing in the backwoods. I already own an awesome backpack that's all broken in. I love it and know where everything is, but it's blue and black.

Is there any non permanant way to camo it? I don't want to do something like spraypaint that will look like crap and be irreversible, but just hate to spend money I could be putting towards other gear. Is camo that important in a backpack, or is more of a marketing thing like a camo barbecue apron LOL???

Opinions and suggestions are greatly appreciated...