There are many verses in the Bible that refer to angels. Only a handful descbibe their appearance, and onlt then the Cherubim race. In Exodus Ch.25: 18-21 we have a description of those that cover the mercy seat on the ark of the covanent. It is described again in Ch. 37: 7-10 of the same book. Again in 2 Chronicles Ch.3: 10-14, we have a description of those that adorned the doors into the Holy place of Solomon's temple.

The pattern that the artists followed was appearantly given to them by God, through his prophet's, Moses in the first case.

Many other instances of angels are found in the Bible, but they usually appear as ordinary looking men in these instances. Whether they are a different race of beings or hide their true appearance from the ones they visited I really can't say.