If there were something in this timeframe I would have thought it would be in CAFO1983 dated 9th October 1941 which does list types of scheme on a variety of ships, but it is silent on HMS Dorsetshire. CAFO1983/41 cancelled CAFO302/41 dated 13th February 1941, but this document doesn't really say anything other than to warn that certain ships will be ordered to camouflage according to Admiralty endorsed designs when they come in for refit in Home Waters. If you're interested, this document does give primary source confirmation of Arethusa, Aurora and Galatea being in Mountbatten Pink which are also listed in your Warship Perspectives Vol.1 as you doubtless recall.
It's not impossible there's something else out there, but personally I'd feel fairly comfortable in Groves' notes as far as the Indian Ocean assignment is concerned.
From her movements records, she appears to have been in Africa and the Indian Ocean from start of the war until assigned to convoy escort immediately prior to being reassigned to join the Bismarck hunt in May 1941, and then she was refitted afterwards. It makes sense that she would have received fresh paint during the refit.
Anecdotal evidence gathered from several persons over many years state that the ship was painted in Mounbatten Pink and light grey.
McClaren Groves, who had a practice of taking detailed notes of various ship's camouflage, including taking paint samples from ship's paint lockers, states that from personal observation of Dorsetshire in the Indian Ocean in late 1941, she was in medium and light grey. This scheme was retained until April 1942 when a different disruptive pattern was adopted. From interpreting my notes it appears that the ship was in Mountbatten Pink in the first half of 1941, before changing over to medium and light grey at some point in the latter half of that year.
Deck colours are unknown.
There is no official record that I know of that gives an answer that would satisfy certain enthusiasts.