Note that American views on Russia are pretty variable and not always in partisan synchronization. The second graph hides that as it happens to start with a long stable position. The first graph is clearer on that.
Prior to July, most news about Russia was about sanctions and Ukraine (both Eastern and Crimea). Such news was overwhelmingly negative and not particularly partisan.
In July, the Barack Obama administration criticized Russian actions in Syria, particularly its role in ending the ceasefire. Donald Trump hailed the Russians for fighting terrorism in Syria. Note that this reinforced Trump's narrative that Obama and Hillary Clinton were weak on fighting terrorism. This created a partisan divide in views on Russia.
This is somewhat complicated by the timeline on Wikileaks. In July, they released some negative information about Democrats. Democrats claimed that the Russians had released it. At the time, Trump commented that if the Russians had Clinton's deleted emails there were people that wanted to see them.
Democrats accused Trump of encouraging Russian espionage, which is rather absurd. No amount of new espionage was going to reveal the emails after they were deleted. So unless Democrats were accusing Clinton of lying about not having a copy of the emails, this wasn't going to work.
In any case, Democrats are more likely to associate Russia with losing their election. Republicans are more likely associate Russia as a potential new ally in the war against terrorism. This is somewhat reinforced by Democrats accusing Russia of helping Trump and hurting Clinton. Trump voters think that they made their own decision. So each chant about Russians interfering with the election pushes Republicans towards Russia. While Clinton voters dislike thinking that anyone could vote for Trump.