To reach Mr Faisal's digit(s) take the R40 Mekkah road out of Riyadh and turn right on to the old Mekkah road towards Dhurma. After about 7km turn right off the road on to a track by an obvious water tower. Head towards the obvious rock pinnacle. Trend north to bypass berms and fences, staying on tracks of variable obviousness. Drive for as long as it is safe and sensible, and walk the last, short bit.
The cache is, for the time being at least, in the obvious wadi in a wadi to the south of the main peak. A great location. 4x4 required (easy driving but bumpy), or a really bashed 2x2 and some skill. Enjoy the friendly camels.
For more fun, scramble up to the foot of the rock towers for great views (although the views are pretty good anyway).