No, it is not true that the color of light with the highest frequency also has the longest wavelength. In fact, it is the opposite. The color of light with the highest frequency has the shortest wavelength.
The electromagnetic spectrum encompasses a wide range of wavelengths, from very short gamma rays to very long radio waves. The different colors of visible light correspond to different wavelengths within this spectrum. The colors of visible light, in increasing order of wavelength, are red, orange, yellow, green, blue, indigo, and violet (ROYGBIV).
Among these colors, violet light has the highest frequency and the shortest wavelength, while red light has the lowest frequency and the longest wavelength. Violet light has a higher frequency than blue, green, yellow, orange, and red light, but it has a shorter wavelength than any of these colors.
So, in summary, the color of light with the highest frequency (violet) has the shortest wavelength, not the longest.