Here's a side by side comparison to a store-bought model which uses a small fluorescent bulb. A pair of phosphorescent indicator cards will help expose the ultraviolet light for comparison.
UVC light is invisible to cameras and human eyes, what we are seeing is the very edge of the spectrum emitted by these lights which falls into the visible range (and some bleaches which will partially convert UVC to white light). Human corneas and nearly all artificial optic materials will absorb these wavelengths.
[Chart below is for illustrative purposes only]
The fluorescent bulb (left) emits a visible 'ice blue' color over a wide area, but the LEDs (right) emit noticeably more intense UVC. Images were taken with each light at a 2 inch distance.