"Take me to your leader" is a cartoon catchphrase, said by extraterrestrial aliens who have just landed on earth in a flying saucer to the first human they happen to meet. It originated in a 1953 cartoon by Alex Graham in The New Yorker magazine. The cartoon depicted two aliens telling a four-legged animal “Kindly take us to your President!” A meta-reference is made in the Douglas Adams novel Life, the Universe and Everything, when Trillian addresses the inhabitants of Krikkit.Here's the cartoon:
"I want you to do something for me", she said, and unexpectedly laughed. "I want," she said, and laughed again. She put her hand over her mouth and said with a straight face, "I want you to take me to your leader."
What about the first actual use of 'leader'? Here's something from 1971, from Boy’s Life [Mar 1971, 90]:
A Martian with orders to bring back an earthling started on his long journey to this planet. He arrived early, when everyone was still asleep. He walked into a gas station and addressed one of the pumps saying “Take me to your leader”. He repeated his request several times but naturally got no reply. When the Martian returned to his spaceship his boss asked for a report. The frustrated Martian replied: “I asked the creature over and over if he would take me to his leader. But he just stood there silently with his tail in his ear.’Earlier examples are easy to come by -- Boy's Life again in 1958:; Life Magazine, 17 June 1957: a 'droodle' called "TAKE ME TO YOUR LEADER, EARTHMAN" Can't find a pre-1953 example though.