It's not a color texture at all, the color of the material is completely uniform - in the real world, this stuff is mixed as a liquid and is a solid color.  What gives foam rubber like this its distinctive appearance is the shape and specularity (and as BB said, the way light bounces around inside it, but I'm not bothering to fake that really).  A photo would be fine, as long as the photo perfectly matched your scene's lighting, which it probably won't.  With a procedural material, the lighting can be changed to pretty much anything and the material is still passable, or at any rate, no worse than the same pic anyhow.

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