Today, I was upgrading from Talend Open Studio for Data Integration version 5.3.0 to Talend Open Studio for ESB version 6.1.0, TOS v6.1.0 have come up with lots of updates.
Out of many updates now studio support curved lines to connect components
But for me I was comfortable with old straight lines like we have in TOS V5.3.0
To get straight lines click Windows >Preferences > Talend >Appearances> Designer
Uncheck Use curved connection style for Job Designer
Click ok, close and open job again.