This seems to be the main riff throughout the song:
6–6–5–5–4–4
6–6–5–5–4–4
6–6–5–5–4–4
8–8–7–7–6–6
8–8–7–7–6–6
6–6–5–5–4–4
6–6–5–5–4–4
6–6–5–5–4–4
6–6–5–5–4–4
8–8–7–7–6–6
8–8–7–7–6–6
6–6–5–5–4–4
6–6–5–5–4–4
6–6–5–5–4–4
6–6–5–5–4–4
8–8–7–7–6–6
8–8–7–7–6–6
6–6–5–5–4–4