You can listen to the visualization anytime of day, however finding a time that feels good for you is best and then do it at that time everyday so it becomes a practice you repeat.
The morning just after waking up is a nice way to welcome your day or it can help you relax and settle into sleep. Anytime of day works though and especially if you're feeling stressed, this is a helpful thing to do in the moment to diffuse the tense energy and shift your body and mind into a more positive and calm state.
Most importantly, do what works for you.