Chocolate Swiss roll is a bit tricky. Why? Because cocoa powder complicates things.
Cocoa powder makes sheet cake less stretchable, so you have to be careful not to overbake the cake. Even slight overbaking makes the cake crack when you roll it.
Cocoa powder also makes the crust sticky, so you have to be careful not to underbake the cake. The more underbaked the crust is, the stickier it is.