You can temporarily change a colorscheme of vim using the following method.
But this change will be transient and as soon as you exit from vim, you will lose the setting. In order to save this setting permanently, you must add this to your .vimrc file
$ vim ~/.vimrc
Add the following lines to the end of the file
Now whenever you open vim, you will see the blue colorscheme. You can use different available vim colorscheme like dessert,darkblue