You can try confining her in a cool, dimly lighted room with her litter box, food and water bowls.
The following may be a bit technical, but it is taken from an informational flyer I am preparing for my vet as a handout to breeders:
"Study results show that the cycles of estrus in the cat have been determined to be dependent on photoperiod. Cats are "long day breeders" and require 12 hours or more of light to maintain normal cycles. Normal polyestrous behavior can be induced by controlling exposure to light. The cycles stopped abruptly in females exposed to less than 8 hours of light. Cycles in the cats resumed an average of 16 days after returning to a 14 hour photoperiod.
The stages of the feline estrus cycle are:
Proestrus - the period preceding estrus, lasts 1 to 2 days. This phase is often unobserved and is seen in only 16% of estrous cycles according to one report. During this time, the female is attractive to but not willing to accept the male. Behavioral changes may begin to be seen during proestrus. The queen may rub against objects, vocalize and assume a lordotic posture; sometimes referred to as a "dragster posture", she will place her front quarters on the ground, elevate her hind quarters and lift her tail to one side. When the dorsal caudal area (the area at the base of the tail) is stroked, she will tread with her hind legs.
Estrus - defined as the period of sexual receptivity. Estrus lasts 3 to 16 days (average of 7) and then subsides for 3 to 14 days (average of 9 days). Behavioral changes are more pronounced in estrus than in proestrus; however, no conspicuous changes in the appearance or size of the external genitalia may be evident. The length of estrus is not affected by breeding or ovulation. The period following estrus is affected by ovulation whether induced by copulation or exogenous hormones.
Interestrus - the period between successive estrus periods if ovulation does not occur. If the queen is not bred, she will cycle into estrus on an average of every 2 to 3 weeks.
Diestrus or pseudopregnancy - Elevated progesterone levels are the hallmark of diestrus. If the queen is not pregnant, diestrus is also termed pseudopregnancy and lasts for 35 to 40 days.
Anestrus - Anestrus is the seasonal period when the cat does not cycle."