Go to ‘Manage this Domain’

Under ‘Organizations and Users’ create an organisation, say ‘Super Admins’ – add the people who you want to run audits, to this Organization.

Go to ‘Services’ (still under ‘Organizations and Users’ )

Scroll down until you find the entry ‘General Audit Tool’

For the entire domain your_domain.tld, set this to ‘Off’ and hit ‘Save Changes’

Next select the Organisation ‘Super Admins’

Again scroll down to the entry ‘General Audit Tool’ and after selecting ‘Override this Setting’

set this to ‘On’ and Remember to ‘Save Changes’

Now the Organisation ‘Super Admins’ should have all rights of the domain and the extra one of running the Audit tool.  You can also enable other Google and non-Google apps for this organization.