Stephanie Locke the create task flow step in Marketo has a number of places where you can populate campaign information. See screenshot. Does that help? or are you asking for something different?
By the way, you should move this to Products, there are more people there that can weigh in, and is typically the place where you would ask questions like this.
To Darrell Alfonso's point, what specifically do you mean by 'link'? As he mentioned, you can certainly customize the Subject and Comments information to give the necessary information around why the task was created.
I'm assuming that these tasks are assigned to either a sales or inside sales individual for follow up, in which case you can add whatever level of detail you need in the task creation flow step. Is there any other relationship you're trying to create other than providing the specific campaign name?
Also, are these tasks created at a Global level, i.e., one smart campaign is listening for specific events across multiple programs, or are these task creation flow steps used within individual programs?