Jabir ibn Samura was asked: “Was there any grayness of the head of Allah’s Messenger (Allah bless him and give him peace)?" He replied: "There was no grayness on the head of Allah’s Messenger (Allah bless him and give him peace), except some hairs in the part of his hair when he applied oil and the oil made them visible.”
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَحْمَدُ بْنُ مَنِيعٍ، قَالَ: حَدَّثَنَا سُرَيْجُ بْنُ النُّعْمَانِ، قَالَ: حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ سِمَاكِ بْنِ حَرْبٍ، قَالَ: قِيلَ لِجَابِرِ بْنِ سَمُرَةَ: أَكَانَ فِي رَأْسِ رَسُولِ اللهِ صلى الله عليه وسلم شَيْبٌ؟ قَالَ: لَمْ يَكُنْ فِي رَأْسِ رَسُولِ اللهِ صلى الله عليه وسلم، شَيْبٌ إِلا شَعَرَاتٌ فِي مَفْرِقِ رَأْسِهِ، إِذَا ادَّهَنَ وَارَاهُنَّ الدُّهْنُ.
sunnah.com