Boro slipped to a fourth straight defeat when they were beaten by the Sky Blues on Saturday and now lie second from bottom in League One.
But Westley said: "The difference between the sides was not huge.
"It was much more like a Stevenage performance, the back four was solid and there was an organisation to our attacking play.
"I'm encouraged by the condition of the players' mind-sets, I'm encouraged by where they are at in terms of their desire and determination, I'm encouraged by their will to learn and change.
"I can see a real will to learn. When as a manager you know that people finally want to take your voice on board, that gives you real optimism."