The victim was attacked after leaving the 155 bus in Balham High Road, south London, at 20:30 GMT on Friday.
The woman was taken to hospital after the attack.
A man from Tooting was charged with two counts of rape and one count of kidnap/false imprisonment on Sunday. The 41-year-old is due to appear at Wimbledon Magistrates' Court on Monday.
Police are trying to find the victim's coat, which went missing after the attack.
Det Insp Melissa Laremore said the red Marks and Spencer jacket has "important evidential value".
She added: "My team are keen to trace a male witness seen on Rinaldo Road, Balham, on the evening of the incident.
"He was wearing a jacket with a distinctive American flag design on the back.
"I would urge him to come forward and contact police."
An 81-year-old woman was raped after being followed when she got off a bus on a busy road, police say.