Painting up CAD Elevations?

Does anyone know the fastest way to paint up 2D CAD elevations using Vendor color samples for the client to choose colors quickly? I thought about scanning the samples then color picking with Photoshop and using color filled shapes on the elevations. Does anyone know a better or faster way of getting accurate color? The client will more than likely change their mind several times so I need a fast workflow.

Thanks!

http://www.colorcharts.org/ccorg/

That is what I use for color selections.