If the installation not work. Try to add manually the i2c configuration. Follow this guide to add i2c on your Raspberry Pi.
After this you can see the slave address that you must add to Cayenne installation page. Try to write on terminal of Raspberry Pi:
sudo apt-get update
sudo apt-get install i2c-tools
sudo i2cdetect -y 1
Now you can see the address. The address is ever 40.