I find watching for the curled arm (squid have 2 tentacles, octos don't have any) to be the easiest to notice. Not all species have enlarged suckers and the size and number of enlarged suckers can vary in individual males. There is also a groove on the arm and a different tip but I can never see them (Mucktopus and Roy say the groove is easy to spot but not with my eyes).
It looks like Beans has nice crypsis patterning so you should see (or miss if you don't look carefully) some interesting variety.
It looks like Beans has nice crypsis patterning so you should see (or miss if you don't look carefully) some interesting variety.