Regardless of the number of strings, visualizing chords is interval based. I think the best resource would be to take the main 4 chord types (M7, dom7, m7, half dim7) and seeing how they look on the fretboard. Given that chords necessarily limit you to a defined range of frets (obviously using open strings can expand the range), it is important to know what vertical relationships exist from any given note.
To start, I would recommend learning major and minor diads in root position, both with thirds and 10ths. These shapes are incredibly important and will crop up in all chords. From there, you can create triads using root - octave - third.
Next step would be to learn where the 7th's are located. Again, root position to start. With this, you can create M7, dom7, m7, mM7, dim7, half dim7, and probably a good number of other chords.
I should add that the 5th of the chord is not needed, other than chords with a modified 5th (diminished, augmented, etc)
From here I would recommend exploring the other chord tones (9th, 11th, 13th), and also inverting the various chords. Not only does this help with knowing the fretboard, but also helps to understand voice leading possibilities. Experiment with transposing tones up or down octaves as available depending on available if you have enough strings or have access to an open string.
