The trichromatic theory is visually represented by a graph plotting cone sensitivity against light wavelength. It shows three overlapping curves, one for each cone type (blue, green, red). The blue cone's sensitivity peaks around 455 nm, the green cone's around 535 nm, and the red cone's around 580 nm. Each curve rises from a low sensitivity, reaches its peak, and then declines, illustrating that each cone type responds to a range of wavelengths but is maximally sensitive to one.