Wa`alaykum As-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Dear brother in Islam, thanks a lot for your question, which reflects your care to have a clear view of the teachings of Islam. Allah commands Muslims to refer to people of knowledge to become well acquainted with the teachings of Islam in all aspects of life.
It is permissible for the husband and wife to enjoy having sexual intercourse in the way they like as long as they avoid that which is unlawful. The husband and wife are absolutely permitted to be fully naked in each other's presence.
In his response to your question, Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states the following:
The Prophet (peace and blessings be upon him) is reported to have said, "Guard your private concealed [parts] except from your marriage partner" (Ibn Hajar).
Based on this, there is no restriction on the married couple exposing themselves in the presence of each other for their mutual enjoyment or pleasure.
Should there be any restriction, the Prophet (peace and blessings be upon him) would have certainly said so, for it is something important for all married couples to know. Since he mentioned nothing, it shall be deemed as belonging to the realm of divine grace, of which the Prophet (peace and blessings be upon him) said, "Whatever He is silent of, it can be deemed as being excused" (Al-Baihaqi and Ibn Hazm).
In conclusion, there is no restriction in nudity when practiced strictly within the bounds of lawful marriage.
Excerpted, with slight modifications, from www.islam.ca.