Graphics processing is generally handled by the processor in computers without dedicated GPU’s (i.e. many laptops). In this case, you’d check the website of the processor’s manufacturer (Intel, AMD, etc) for this info. This can be quite a bit trickier, as there are many more CPU’s out there than GPU’s.
The visualizer is a 2D rendering of a gcode file. This isn’t very taxing to process, so you definitely don’t need a high-end laptop or a desktop computer with a dedicated GPU to handle it.
Keep in mind that OpenGL was released in late 2008, and it takes time for technology to become ubiquitous. Higher-end desktop GPU’s were the first to adopt it, and integrated graphics were the last. I’d try to make sure any laptop you’re looking at was manufactured 2012 or later, just to be safe.