Uses the new Onelogin PHP-SAML Toolkit. Review its dependences

In order to install it, move the onelogin-saml-sso inside the wp-content/plugins folder. Once moved, activate the plugin and configure it.

P.S This plugin will be available at wordpress site soon.

This kind of WP hosting used to cache plugins and protect the wp-login.php view. You will need to contact them in order to disable the cache for this SAML plugin and also allow external HTTP POST to wp-login.php