All the information we provide is only guaranteed under the specified conditions (0 to 85°C). Unfortunately we have no documentation regarding the MPX2010 response in the range you need.
This device has a differential output; therefore you’d need an instrumental amplifier. What I can suggest you is to test both, the sensor and your amplifier in the -40° to 40°C, so you can characterize the full system response. Your amplifiers gain factor would change as well as the sensors behavior.
The MPX2010 is a linear device but the temperature factor would change from one range to another, i.e. the transfer function would not be the same at -40°C than at -10°C.
Once you have the system response in the full range (you already have from 0 to 40°C) you can generate a transfer function to obtain the pressure value. I’d also recommend you to use a microcontroller with an integrated temperature sensor, so you can change your temperature factor as needed.
Hope it helps. =)