Regular uncolored plain concrete should be pretty light, like you're seeing on sidewalks. (It might require occasional powerwashing to keep it light.) If that color works for you, you should explain to your contractor. He might say it's a bad choice--it IS the cheap one! But if that's the color you want...

When we've had concrete poured, it's had dark stuff added to make it look grayer like the 70-year old stuff in the neighborhood. A new pool equipment pad off in the back is the plain white and it's pretty light!

Colored concrete cannot be guaranteed to be the same as a sample color. HERE is an article that explains why. Also, it takes 28 days for concrete to cure, so its "actual" color will change during that interval.

I agree with Fori that plain, cured concrete should be pretty light. However, there is another way to color concrete—staining. As long as your concrete has not been sealed you can stain it. I believe this applies to colored concrete as well; however, you should consult a concrete stain professional. The only stain I am familiar with is Surecrete's Eco Stain, which is DIY, and there is a "white". Nonetheless, the vagaries noted in the article I referenced in my first paragraph apply to stains as well.

We too are trying to get a creamy colored concrete for new pool. Seems impossible according to suppliers around here. Any updates in your search?

lime will lighten the concrete when used in conjunction with cement but there are issues with moisture so may not be suitable for poolside applications.