Mira Murati, chief executive of Thinking Machines Lab. David Paul Morris/Bloomberg via Getty Images AI startup Thinking Machines Lab is set to close a fresh round of funding as soon as this week.The startup is raising $5 billion at a $40 billion pre-money valuation, according to multiple sources familiar with the matter. Accel is leading the round, according to the sources. Previously, Thinking Machines Lab, which was founded by Mira Murati, was valued at more than $10 billion and raised a $2 bi...