The Red Sea by Sybil Taylor is the best single volume on Red Sea diving, covering the major sites from Hurghada to the Sudanese border with good underwater photography and site descriptions.
Egypt (Lonely Planet) has a reliable chapter on the Red Sea coast with practical logistics. The DK Eyewitness guide is better for cultural context and planning day trips to Luxor and the ancient sites.
For history and context, The Nile by Toby Wilkinson is excellent background reading before visiting Egypt's interior sites on day trips from Hurghada.