First we clone the content from GitHub:

/usr/local/cpanel/3rdparty/bin/git clone https://github.com/pagespeed/cpanel.git /tmp/pagespeed/

Now we extract and move the module:

cd /tmp/pagespeed/Easy

tar -zcvf Speed.pm.tar.gz pagespeed

mkdir -p /var/cpanel/easy/apache/custom_opt_mods/Cpanel/Easy

mv Speed.pm Speed.pm.tar.gz -t /var/cpanel/easy/apache/custom_opt_mods/Cpanel/Easy/

You can now remove the /tmp/pagespeed directory which was created.

Now recompile using EasyApache in the Web Host Manager and make sure to select mod_pagespeed on Short Options List