Short version: they looked a lot more like 
than 
. Most accounts of Vikings that are contemporary of the centuries where shield-Danes and spear-Danes went "a-Viking" describe distinctly hygenic people that bathed and took care of their hair (and wore it long).
EDIT: I thought I could have a little fun with a very loosely associated Beowulf reference to Danes (and even more loose associations with Geats therein too) but I got the 
experience for doing so. 
They didn't have Hitler Youth fades with lazy and sloppy beard fusions. Period. Full stop. Stop doing that. Looking right the fuck at you too, P R E S T I G E T V. 
those are normans though, arent they? not saying they didnt wear a norse hairstyle but they were pretty far removed culturally from their norse roots at that point, so maybe it's not a norse hairstyle but a specifically norman (or shudder french) hairstyle
its a norman-made tapestry, it depicts other kinds of people.
but typing hairstyles to cultures based on 1 (one) source is pretty silly regardless, all we can definitively say is that some people round 1066 wore a hairstyle that got represented in that way, we don't know how it was worn or for what purpose