Just let the site expire.
Keep in mind, you can use the site for another guild.
Alternatively, some guilds will change the address of the site to something like "deadguild.dkpsystem.com" and then they reset the site to make it blank.
The last option is just to make a news post that says "Our guild is no more. The site will remain here until it expires."
I'd rather just take it down or just leave up a picture saying the guild is done
any way i can just post a picture ...
e.g. they click on the guild website and it just takes them to a picture with no links