Just been trying this with Automator.
Run Automator, click 'application' then 'Choose'
Type Run shell script into the search bar and then drag the action into the window.
type in
pmset -g log|grep -e " Sleep " -e " Wake "
in the search bar type New TextEdit Document
and drag that below you previous window
save with a meaningful name
then you just need to click the icon to run the script and show the results