You see, a single carbon-carbon bond in most molecules averages around 1.5 angstroms in length, where 1 angstrom = 1x10^-10 meters. So, for triacylglycerol palmitic acid (16-C, saturated) side chains (plus let's say 3 angstroms of added length for the glycerol C-O-C bond) we'd have a total maximum length (assuming the molecules are completely stretched out, i.e., all bond angles = 180 degrees) of only 19 angstroms, or 1.9 nanometers.
Given that the visible portion of the electromagnetic spectrum only extends down to wavelengths of about 350nm, this size as a photon wavelength would lie solidly in the ultraviolet portion of the spectrum. In other words, an individual triacylglyceride molecule would probably be invisible to the naked human eye even if we had a visible microscope capable of such precise focusing because the molecule would be too small of an object to reflect a photon of visible light.
That is, unless we genetically engineered some super-intelligent species of bird (many of which, like the above Kestrel, can see UV light), provided it with a unique linguistic diction capable of identifying ranges of the UV spectrum as specific colors, sat it down in front of a futuristic (specially designed with avian ergonomics in mind) ultra-violet spectrum microscope pointed at some tracylglyceride molecules, then asked it to tell us what it saw.
That would be a cool experiment. I'd put my name on that paper.