Succulents come in a wide range of colors, and the same plant can even look different at different times of the year. In general, you can expect the brightest colors in the spring and more green tones in winter.
That said, fading and greening can be signs that a succulent is not getting enough light. If a succulent is not getting enough light, it will also usually stretch at the stem as it tries to reach more sunlight. Succulents experience a light shortage during shipment but the effects are quickly reversed with a gradual transition back into sunny conditions. If a succulent has been kept in too little light for a long time, you can improve its coloration by moving it outdoors (weather permitting), keeping it closer to a sunny window, or using a dedicated grow light on it. Stretching will not reverse, but you can prune and repot succulents to get them back into a tidy, compact form.
Please note: While it is possible to grow hardy succulents indoors, they will usually be green and slightly stretched from a lack of sunlight indoors.