Lets jump straight in with the pictures.
Step1: Undercoated black and then Adeptus Battlegrey.
Step2: Drybrushed all over with Codex Grey. Hair painted with Ice Blue.
Step3: Drybrushed all over with Fortress Grey.
Step4: Drybrushed all over with Astronomican Grey.
Step5: Inside of mouth painted with Mechrite Red. Little “rocky” bits painted Regal Blue. Wash of Asurmen Blue then Ogryn Flesh all over.
Step6: “rocky” bits highlighted with Enchanted Blue and washed with Asurmen Blue. Hair highlighted with white.
Step7: Teeth and nails painted with Deneb Stone. Loincloth painted with Khemri Brown and Calthan Brown then washed with Delvan Mud. Base painted and flocked.
Quite a simple model to paint, and mostly hassle free!