Mujahid narrated: Sayyidah Umm Salamah (may Allah be pleased with her) was asked whether a woman may cover her face while in the state of ihram. She said: "Riders used to pass by us while we were with the Prophet (peace and blessings be upon him), and one of us would let a cloth hang down over her face."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20236