Colouring plain concrete

Short story - I was supposed to have a bluestone coloured concrete front porch to match the bluestone coloured concrete driveway that will be put in later.

When the slab was laid, they also did the porch - in plain concrete. I'm trying to get the builder to rectify it but I'm worried they'll come back and say the only way to fix it is to paint it to match and I've been told definitely don't let them do that as I will have to repaint every year (and it doesn't look very good).

Are there ways for them to fix this, like staining the concrete, and what is the best option? I basically would like to know the options before they call me and tell me what option they think is best.