According to Osho, sannyas must be colorful because, once you see everything is empty, all possibilities blossom; the sannyasin becomes a rainbow. He chose orange/red to symbolize life-affirming celebration, not grim renunciation—flowering energy that contains the whole tree of life. This vibrant hue declares playfulness, sincerity without seriousness, and living in the world like a lotus: untouched yet rejoicing.
Orange shows that when you realize everything is empty, you can joyfully bloom in life without clinging.