To enable or disable the Music in the game, go to the 'Settings' menu. To do this, select the gear icon in the top left corner of your main screen.
Once you are there, you will see the music option, right below 'Sounds'. To enable or disable the Music, simply check the option, by swiping to the side. You will see that the Sound icon turns green/blue and the Music icon, represented by eighth-notes, will be crossed out by a red line when disabled.