The colors in sandstone are imparted after lithification (turning to stone). Carried by ground water, chemical oxides seep through the rock and deposit in small amounts to create the red and yellow hues. Afterwards, reducing chemicals flow through the same rock dissolving the oxides bleaching parts of it white. There is an obvious flow here that seems associated with the shape of the small hill, though it's likely coincidental that erosion revealed it in this manner.