In some cases the kraken is represented as an octopus, or even as a bearded whale. So it depends, really.
I think the myth does originate partially from giant squids, but it’s “glued” with knowledge of smaller cephalopods; it’s easy to picture an octopus but giant, you know? The bearded whale depiction might be related too, possibly some whale hunting a giant squid (they sometimes do it).
In some cases the kraken is represented as an octopus, or even as a bearded whale. So it depends, really.
I think the myth does originate partially from giant squids, but it’s “glued” with knowledge of smaller cephalopods; it’s easy to picture an octopus but giant, you know? The bearded whale depiction might be related too, possibly some whale hunting a giant squid (they sometimes do it).