I don't know about Sweden specifically, but usually in Europe if you're under 30, you can just get a working visa, show up and look for work. If you're 30 or over, you need to have an offer of work before you can get a working visa.
Yes, you can show up, but you won't get a job unless you speak fluent Swedish. Maybe if you are a specialised engineer/IT. Even then, the Swedish applicant will be picked first.
Back when I was 31, I considered the antipodean tradition of getting a working visa somewhere in Western Europe and doing odd jobs ('bar work' is the traditional one, but I would have gone for other unskilled labour). A sort of working holiday. Then I found out about the 30-year-old cut-off...
In my experience this is not at all true. I would say that Swedes are known for their fluency in English and not knowing any Swedish, but speaking English, is not a problem in Sweden at all. I have people at my job that have lived here for 7-8 years and have still not learned to speak Swedish but manage to stay employed regardless.If you speak English and is good at what you do, you will find a job.
