The directory where the queries are saved is controlled by the variable $ADODB_CACHE_DIR

The parameter $cacheSecs sets the default value of the time in seconds that cached queries are saved. If not set then the value is 3600. It can be set via either a normal connection object or a DSN type connection configuration.

This default value can be overridden on a query by query basis

/*
 * A connection object assumed
 */
$ADODB_CACHE_DIR = 'd:/queries';
$db->cacheSecs   = 6000;