How to step down analog sensor signal voltage using voltage divider
When you select resistors for use in a voltage divider there are a couple of things you need to take into account. In your case it is the output impedance of the sensor, roughly speaking how much current it can supply without messing up the output voltage, and the input impedance of the ADC.

The input impedance of a ADC will be very high, usually it is the input to a comparator. This means that you can use large value resistors. The total resistance for the voltage divider, as a rule of thumb should be at least 10 times the output impedance of the sensor. The values suggested by @Jasen 10k and 51k are reasonable.