Firstly, check that the vim-enhanced package is installed :

rpm -qa | grep vim

You should see something like :

vim-common-6.2.98-1
vim-minimal-6.2.98-1
vim-enhanced-6.2.98-1

If the vim-enhanced package is not installed, download the package and run :

sudo rpm -i vim-enhanced-6.2.98-1.rpm

You will probably have to exit your terminal and reconnect before any changes are visible.

If you are still having problems, check that the line

syntax on

is uncommented in /etc/vimrc. If you want to customize coloring for different users, copy /etc/vimrc to .vimrc in your home directory, and make the changes there.

You might also want to turn off the annoying search highlighting by commenting out the line

set hlsearch