In the middle of this bright yellow prayer cloth is the symbolic circular sun with numerous rays. Within the circumference are human features with the mark of Vishnu on the forehead. On the vertical ends are similar but smaller depictions. Since the sun is an important element of worship in Hindu ritual life, each morning the mantra which invokes the sun is chanted by priests wearing a prayer cloth such as this. A particular verse dedicated to Savitar (one of sun's name in its manifestations as the procreator) referred to in the Rig Veda is still uttered three times a day and is called the Gayatri mantra.
Red, the colour of energy sits very well on yellow, the pious colour signifying sun as the source of energy and sacredness.
This description by Kiranjyot.