I hope you have a lot of money.
For graphics design, you're pretty limited in your choices. The Macbook Pros are the obvious choice. They're readily available and come with screens calibrated for 100% sRGB color space coverage. Dell, Lenovo, and HP all have graphics workstations with optional screens that can cover 100% sRGB or even AdobeRGB. But they cost the same or even more than the MBPs. Look for the laptops with a Sharp IGZO screen - those tend to hit 100% sRGB or close to it. The Dell XPS 15 pretty much matches the 15" MBP. The HP Probook and Thinkpad W5xx have options for AdobeRGB screens, but are a lot chunkier.
If complete sRGB color gamut coverage isn't necessary, then lots of PC laptops will work. Typical laptop...