Currently there is no ability to upload a custom email template for a daily log.
For every other module where you have the ability to email from, you can do a custom email template to match your company's desired font, signature, logo etc but with no ability to upload a custom one, you are stuck with using the SageCM default one.
These daily logs do get emailed out externally so not being able to have them appear like your other emails isn't a great look.