“Better color” is mostly subjective marketing. In practice, lenses can differ in color rendering because they do not transmit all wavelengths of light equally. The main causes are the lens element materials and the coatings, which can make a lens look slightly warmer, cooler, or alter saturation a bit.

These differences are often more noticeable with older lenses than with modern ones. With most modern lenses, any color differences are usually small, and custom white balance or post-processing can largely correct them. Auto white balance may also make lens-to-lens differences seem more obvious.

So yes, lenses can produce slightly different color casts, but that is not the same as one lens having objectively “better” color. For accurate color, camera profiling, white balance, lighting, and post-processing usually matter more than the lens. Also, sample images in marketing are often edited, so it can be hard to tell what comes from the lens and what comes from post-processing.