Go to www.amarillolibrary.org and look for online resources. Under ask-a-librarian request a lookup of the obit. They have been very helpful and respond quickly.

Per www.findagrave.com Cab Calloway b. Jun. 8, 1900 d. Jun. 27, 1981 Interment: July 3, 1981 Llano Cemetery, Potter county, Amarillo TX.

Also listed at findagrave. Llano Cemetery, Myrtle Louise Calloway Photo & Obit posted and Alexander Calloway Jr. obit posted.

I hope this helps.
Millie