Raul,

 

The cancel-all-button is generated by script. If you want to customize it, you can try this way :

 

 

 

And these css classes can help you:
AjaxUploaderProgressTable
AjaxUploaderProgressBarText
AjaxUploaderProgressInfoText
AjaxUploaderQueueTable
AjaxUploaderCancelAllButton
AjaxUploaderQueueTableRow

 

Regards,

Terry