I can find several qualitatively different diagrams of the responsiveness of human cones and rods to different wavelengths of light.
Very similar plots (with the same truncation for M and L cones, and the same slight rise in sensitivity at shorter wavelengths) can be found here.
For a graph with an even sharper nonmonotonicity of the L cone at blue wavelengths, see here.
My vague impression is that the second category of graphs tends to come from more recent or reputable sources, but I'm very unsure about this, and in general I'm confused why there seems to be so much disagreement here. Are there good survey articles that discuss this discrepancy and the reasons for it?