No, the Mukaitaki Ryokan does not open their baths to non-staying guests.More than half of the other ryokan in Higahsiyama Onsen do open their baths to daytime visitors, however, I have not been to any of them and cannot make a recommendation based on personal experience.
But by judging from the ryokan's websites, I can't help mentioning the Toho. Their baths look quite spectacular:
http://www.onyado-toho.co.jp/
Two more places with nice looking baths on their websites:
http://shousuke.com/
http://www.kutsurogijuku.jp/